I found the project idea for Mushroom Spore Prints in a book I borrowed from the
library this week: Nature Printing with Herbs, Fruits, & Flowers by Laura Donnelly
Bethmann (1996, Storey Publishing ISBN 0-88266-929-X) p.53-53:

Mushroom Spores

"Superstitions and stories abound about the fungi we call mushrooms, which spring up
with amazing rapidity in warm, moist places. Long associated with fairies, elves,
and witches, some delicious mushrooms are edible, but some are deadly. The part of
the mushroom growing aboveground is the fruiting body, and the growing mass of dense
white mycelium underneath the ground is the vegetative part."

"Containing no chlorophyll, mushrooms are never green, but they may be pink, white,
red, yellow, lavender, silvery blue or orange, and exhibit a variety of shapes. The
common field mushroom is white with pinkish-brown gills, with platelike growths
radiating underneath the cap. Spores develop on each side of the gills. Very small
one-celled organisms, spores are like the seeds of flowering plants that scatter
with the wind and develop into new mycelium, sometimes living for centuries."

To print mushrooms, you will need the following materials:
Mushrooms
Light and dark colored papers
Cups or glasses
Artist's spray fixative"

"reparation for Printing
Cut the stem off at the cap of a mushroom and lay the cap on a sheet of paper with
the gills facing the paper. For dark spores, use white paper, for light spores, use
black paper. If you are unsure of the color, make prints on both light and dark
colored paper."

"rinting
Place an inverted cup or glass over the mushroom cap and leave it undisturbed for 12
- 24 hours. Remove the glass and the cap to reveal the pattern of spores that have
shed along the lines of the radiating gills. To keep the print intact, spray with
one or two coats of pastel or charcoal artist's fixative."